70cc kit question

Tomos a35......so i put on a 70cc kit, high flow air filter, and techno boss pipe. I'm seeing only a marginal increase in power/speed. Slow start off and top at 40ish on flat. It has a 61 jet in it. What an I doing wrong?

Re: 70cc kit question

Cleats Onionpockets /

You haven't jetted it high enough. Not even close. Go up about 10 jet sizes for a start, and report back.

Re: 70cc kit question

> Dre Snow Wrote:

> -------------------------------------------------------

> Tomos a35......so i put on a 70cc kit, high flow air filter, and techno

> boss pipe. I'm seeing only a marginal increase in power/speed. Slow

> start off and top at 40ish on flat. It has a 61 jet in it. What an I

> doing wrong?

What intake and carb?

Re: 70cc kit question

Is it slower off the line than it was before you kitted it?

Re: 70cc kit question

Ok, bigger jet is helping but now sometimes at full throttle, the engine bucks like it losing power for a second?

Re: 70cc kit question

What jet did you jump to?

Re: 70cc kit question

Too big or maybe still too small, but likely too big. Report back.

Re: 70cc kit question

Went up to 65, seemed too Bucky, went to 63, and same. Going back to 61

Re: 70cc kit question

bucking can also be from the intake, if your engine is starved for air you're not going anywhere fast.

Re: 70cc kit question

Seems to have gained speed but the bucking is now worse. It almost feels like a rev limiter kicking in but it’s not that. Could an air leak cause this? It’s at full throttle that it cuts in and out for a second and bucks. This is nuts.

Re: 70cc kit question

Brandon Weiss (Detective brandon to you) /

There can be other factors at play here that you aren't considering. You could have air leaks at the base gasket or your crank seals.

If you used the included base gasket with the kit, they are often undersized and can block airflow.

Typically, a run of the mill tomos 44 or 45mm kit will want in the low 70's for jetting on a stock intake with the 14/12sha. 61 is way too low.

Let's have a look at the spark plug?

Re: 70cc kit question

I’m worried it is soft seizing. Maybe the power breaks and bucking are that?

Re: 70cc kit question

65 is still not big enough.

Re: 70cc kit question

69 jet is the biggest I have so I put that on. Haven’t ran it yet but I’m worried the smaller jets made it soft seize. Feels ok now and we will see. Any advice on possible soft seizing happening?

Re: 70cc kit question

Cleats Onionpockets /

It's possible. Do a compression test, and order some bigger jets.

Re: 70cc kit question

A soft seize will generally always stop the engine and your ride at least temporarily.

Re: 70cc kit question

I have a 70cc kit on my 1996 tomos sprint. Anyone know what my gauge should be on the spark plug? I was running a stock b6hs and recently changed to a b7hs because of the kit. It seems to be running better but I haven't changed that gap at all....Should I be running a b8hs? I'm so lost when it comes to finding the right spark plug. I'm a new rider and just bought the used bike last month (edited)

Re: 70cc kit question

Dirty30 Dillon /

6 or 7 is fine, and really whatever gap you'd like. The majority of bikes the gap won't play a huge part. Leave it whatever it was out the box.

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account